Haematological malignancies in a general population, based on information collected from a population study, hospital records, and the Cancer Registry of Norway: the Tromsø Study.

Objectives: To investigate the prevalence and incidence of haematological malignancies, and to compare the rates found with those reported from the Cancer Registry of Norway.

Methods: Three sources of information were used: (1) automated blood cell counts from 27 145 persons older than 24 yr (72% of those invited), participating in a population study (the Tromsø Study 1994-95); (2) patient medical records at the University Hospital of Tromsø during 1991-96; (3) the Cancer Registry of Norway.

Results: (1) In the population study, 13 new cases of haematological malignancies were diagnosed. For five of these the early detection was probably beneficial. (2) From the hospital records another 59 participants and 36 non-participants to the population study were found to have haematological malignancies. (3) Additionally, six cases were identified from the Cancer Registry. Totally, we thus identified 114 period prevalent cases, of which 86% had been reported to the Cancer Registry. Age-adjusted period prevalence of haematological malignancies was 4.7 per thousand in men and 2.9 per thousand in women. The prevalence increased with age. There were 84 cases with leukaemia, lymphoma, or multiple myeloma diagnosed at any time and still alive at 31 December 1996 (point prevalence 2.2 per thousand). Our estimated incidence of haematological malignancies did not differ significantly from that reported from the Cancer Registry.

Conclusion: We found approximately the same rates of haematological malignancies as the Cancer Registry, although an underreporting of 14% to the Cancer Registry was detected. The point prevalence of leukaemia, lymphoma, and multiple myeloma was 2.2%.